Enabling secure state-clean during configuration of partial reconfiguration bitstreams on fpga

ABSTRACT

An apparatus to facilitate enabling secure state-clean during configuration of partial reconfiguration bitstreams on accelerator devices is disclosed. The apparatus includes a security engine to perform, as part of a PR configuration sequence for a new partial reconfiguration (PR) persona corresponding to a PR bitstream, a first clear operation to clear previously-set persona configuration bits in the region; perform, as part of the PR configuration sequence subsequent to the first clear operation, a set operation to set new persona configuration bits in the region; and perform, as part of the PR configuration sequence, a second clear operation to clear memory blocks of the region that became unfrozen subsequent to the set operation.

RELATED APPLICATIONS

This application is a continuation of 17/129,250 filed on Dec. 21, 2020, which claims the benefit of priority from U.S. Provisional Pat. Application Serial No. 63/083,783 filed on Sep. 25, 2020, now expired, the full disclosure of which is incorporated herein by reference.

FIELD

This disclosure relates generally to data processing and more particularly to enabling secure state-clean during configuration of partial reconfiguration bitstreams on FPGA.

BACKGROUND OF THE DISCLOSURE

A programmable logic device can be configured to support a multi-tenant usage model. A multi-tenant usage model arises where a single device is provisioned by a server to support N clients. It is assumed that the clients do not trust each other, that the clients do not trust the server, and that the server does not trust the clients. The multi-tenant model is configured using a base configuration followed by an arbitrary number of partial reconfigurations (i.e., a process that changes only a subset of configuration bits while the rest of the device continues to execute). The server is typically managed by some trusted party such as a cloud service provider.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above recited features of the present embodiments can be understood in detail, a more particular description of the embodiments, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate typical embodiments and are therefore not to be considered limiting of its scope.

FIG. 1 is a diagram of an illustrative programmable integrated circuit in accordance with an embodiment.

FIG. 2 is a diagram showing how configuration data is created by a logic design system and loaded into a programmable device to configure the device for operation in a system in accordance with an embodiment.

FIG. 3 is a diagram of a circuit design system that may be used to design integrated circuits in accordance with an embodiment.

FIG. 4 is a diagram of illustrative computer-aided design (CAD) tools that may be used in a circuit design system in accordance with an embodiment.

FIG. 5 is a flow chart of illustrative steps for designing an integrated circuit in accordance with an embodiment.

FIG. 6 is a diagram of an illustrative multitenancy system in accordance with an embodiment.

FIG. 7 is a diagram of a programmable integrated circuit having a static region and multiple partial reconfiguration (PR) sandbox regions in accordance with an embodiment.

FIG. 8 illustrates a computing device employing a disaggregate compute component, according to implementations of the disclosure.

FIG. 9 illustrates a disaggregate compute component, according to one implementation of the disclosure.

FIG. 10 illustrates a network environment implementing an Infrastructure-as-a-Service (IaaS) usage model having secure-state leaking across mutually-distrustful tenants.

FIG. 11 illustrates a network environment implementing a PR configuration flow for secure state clean of an accelerator device, in accordance with implementations of the disclosure.

FIG. 12 illustrates a field-programmable gate array (FPGA) fabric for implementing partial reconfiguration (PR) ownership regions, in accordance with implementations of the disclosure.

FIG. 13 illustrates a conventional PR configuration flow for an accelerator device, in accordance with implementations of the disclosure.

FIG. 14 illustrates a PR configuration flow for secure state clean of an accelerator device, in accordance with implementations of the disclosure.

FIG. 15 is a flow diagram illustrating a method 1500 for enabling secure state-clean during configuration of partial reconfiguration bitstreams on FPGA, in accordance with implementations of the disclosure.

DETAILED DESCRIPTION

Implementations of the disclosure describe enabling secure state-clean during configuration of partial reconfiguration bitstreams on FPGA. Disaggregated computing is on the rise in data centers. Cloud service providers (CSP) are deploying solutions where processing of a workload is distributed on disaggregated compute resources such as CPUs and hardware accelerators, such as FPGAs, that are connected via network instead of being on the same platform and connected via physical links such as PCIe. The compute disaggregation enables improved resource utilization and lowers Total Cost of Ownership (TCO) by making more efficient use of available resources. Disaggregation also enables pooling a large number of hardware accelerators for large computation making the computation more efficient and performant. The term “whitelist” is used in this disclosure only for their technical meaning. The term “whitelist” may be substituted with the term “allowlist”.

In the following description, numerous specific details are set forth to provide a more thorough understanding. However, it may be apparent to one of skill in the art that the embodiments described herein may be practiced without one or more of these specific details. In other instances, well-known features have not been described to avoid obscuring the details of the present embodiments.

Various embodiments are directed to techniques for disaggregated computing for programmable integrated circuits, for instance.

System Overview

While the concepts of the present disclosure are susceptible to various modifications and alternative forms, specific embodiments thereof have been shown by way of example in the drawings and are described herein in detail. It should be understood, however, that there is no intent to limit the concepts of the present disclosure to the particular forms disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives consistent with the present disclosure and the appended claims.

References in the specification to “one embodiment,” “an embodiment,” “an illustrative embodiment,” etc., indicate that the embodiment described may include a particular feature, structure, or characteristic, but every embodiment may or may not necessarily include that particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art to effect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described. Additionally, it should be appreciated that items included in a list in the form of “at least one A, B, and C” can mean (A); (B); (C); (A and B); (A and C); (B and C); or (A, B, and C). Similarly, items listed in the form of “at least one of A, B, or C” can mean (A); (B); (C); (A and B); (A and C); (B and C); or (A, B, and C).

The disclosed embodiments may be implemented, in some cases, in hardware, firmware, software, or any combination thereof. The disclosed embodiments may also be implemented as instructions carried by or stored on a transitory or non-transitory machine-readable (e.g., computer-readable) storage medium, which may be read and executed by one or more processors. A machine-readable storage medium may be embodied as any storage device, mechanism, or other physical structure for storing or transmitting information in a form readable by a machine (e.g., a volatile or non-volatile memory, a media disc, or other media device).

In the drawings, some structural or method features may be shown in specific arrangements and/or orderings. However, it should be appreciated that such specific arrangements and/or orderings may not be required. Rather, in some embodiments, such features may be arranged in a different manner and/or order than shown in the illustrative figures. Additionally, the inclusion of a structural or method feature in a particular figure is not meant to imply that such feature is required in all embodiments and, in some embodiments, may not be included or may be combined with other features.

Programmable integrated circuits use programmable memory elements to store configuration data. During programming of a programmable integrated circuit, configuration data is loaded into the memory elements. The memory elements may be organized in arrays having numerous rows and columns. For example, memory array circuitry may be formed in hundreds or thousands of rows and columns on a programmable logic device integrated circuit.

During normal operation of the programmable integrated circuit, each memory element is configured to provide a static output signal. The static output signals that are supplied by the memory elements serve as control signals. These control signals are applied to programmable logic on the integrated circuit to customize the programmable logic to perform a desired logic function.

It may sometimes be desirable to reconfigure only a portion of the memory elements during normal operation. This type of reconfiguration in which only a subset of memory elements are being loaded with new configuration data during runtime is sometimes referred to as “partial reconfiguration”. During partial reconfiguration, new data should be written into a selected portion of memory elements (sometimes referred to as “memory cells”).

An illustrative programmable integrated circuit such as programmable logic device (PLD) 10 is shown in FIG. 1 . As shown in FIG. 1 , programmable integrated circuit 10 may have input-output circuitry 12 for driving signals off of device 10 and for receiving signals from other devices via input-output pins 14. Interconnection resources 16 such as global and local vertical and horizontal conductive lines and buses may be used to route signals on device 10. Interconnection resources 16 include fixed interconnects (conductive lines) and programmable interconnects (i.e., programmable connections between respective fixed interconnects). Programmable logic 18 may include combinational and sequential logic circuitry. The programmable logic 18 may be configured to perform a custom logic function.

Examples of programmable logic device 10 include, but is not limited to, programmable arrays logic (PALs), programmable logic arrays (PLAs), field programmable logic arrays (FPLAs), electrically programmable logic devices (EPLDs), electrically erasable programmable logic devices (EEPLDs), logic cell arrays (LCAs), complex programmable logic devices (CPLDs), and field programmable gate arrays (FPGAs), just to name a few. System configurations in which device 10 is a programmable logic device such as an FPGA is sometimes described as an example but is not intended to limit the scope of the present embodiments.

Programmable integrated circuit 10 contains memory elements 20 that can be loaded with configuration data (also called programming data) using pins 14 and input-output circuitry 12. Once loaded, the memory elements 20 may each provide a corresponding static control output signal that controls the state of an associated logic component in programmable logic 18. Typically, the memory element output signals are used to control the gates of metal-oxide-semiconductor (MOS) transistors. Some of the transistors may be p-channel metal-oxide-semiconductor (PMOS) transistors. Many of these transistors may be n-channel metal-oxide-semiconductor (NMOS) pass transistors in programmable components such as multiplexers. When a memory element output is high, an NMOS pass transistor controlled by that memory element can be turned on to pass logic signals from its input to its output. When the memory element output is low, the pass transistor is turned off and does not pass logic signals.

A typical memory element 20 is formed from a number of transistors configured to form cross-coupled inverters. Other arrangements (e.g., cells with more distributed inverter-like circuits) may also be used. With one suitable approach, complementary metal-oxide-semiconductor (CMOS) integrated circuit technology is used to form the memory elements 20, so CMOS-based memory element implementations are described herein as an example. In the context of programmable integrated circuits, the memory elements store configuration data and are therefore sometimes referred to as configuration random-access memory (CRAM) cells.

An illustrative system environment for device 10 is shown in FIG. 2 . Device 10 may be mounted on a board 36 in a system 38. In general, programmable logic device 10 may receive configuration data from programming equipment or from other suitable equipment or device. In the example of FIG. 2 , programmable logic device 10 is the type of programmable logic device that receives configuration data from an associated integrated circuit 40. With this type of arrangement, circuit 40 may, if desired, be mounted on the same board 36 as programmable logic device 10.

Circuit 40 may be an erasable-programmable read-only memory (EPROM) chip, a programmable logic device configuration data loading chip with built-in memory (sometimes referred to as a “configuration device”), or other suitable device. When system 38 boots up (or at another suitable time), the configuration data for configuring the programmable logic device may be supplied to the programmable logic device from device 40, as shown schematically by path 42. The configuration data that is supplied to the programmable logic device may be stored in the programmable logic device in its configuration random-access-memory elements 20.

System 38 may include processing circuits 44, storage 46, and other system components 48 that communicate with device 10. The components of system 38 may be located on one or more boards such as board 36 or other suitable mounting structures or housings and may be interconnected by buses, traces, and other electrical paths 50.

Configuration device 40 may be supplied with the configuration data for device 10 over a path such as path 52. Configuration device 40 may, for example, receive the configuration data from configuration data loading equipment 54 or other suitable equipment that stores this data in configuration device 40. Device 40 may be loaded with data before or after installation on board 36.

As shown in FIG. 2 , the configuration data produced by a logic design system 56 may be provided to equipment 54 over a path such as path 58. The equipment 54 provides the configuration data to device 40, so that device 40 can later provide this configuration data to the programmable logic device 10 over path 42. Logic design system 56 may be based on one or more computers and one or more software programs. In general, software and data may be stored on any computer-readable medium (storage) in system 56 and is shown schematically as storage 60 in FIG. 2 .

In a typical scenario, logic design system 56 is used by a logic designer to create a custom circuit design. The system 56 produces corresponding configuration data which is provided to configuration device 40. Upon power-up, configuration device 40 and data loading circuitry on programmable logic device 10 is used to load the configuration data into CRAM cells 20 of device 10. Device 10 may then be used in normal operation of system 38.

After device 10 is initially loaded with a set of configuration data (e.g., using configuration device 40), device 10 may be reconfigured by loading a different set of configuration data. Sometimes it may be desirable to reconfigure only a portion of the memory cells on device 10 via a process sometimes referred to as partial reconfiguration. As memory cells are typically arranged in an array, partial reconfiguration can be performed by writing new data values only into selected portion(s) in the array while leaving portions of array other than the selected portion(s) in their original state.

It can be a significant undertaking to design and implement a desired (custom) logic circuit in a programmable logic device. Logic designers therefore generally use logic design systems based on computer-aided-design (CAD) tools to assist them in designing circuits. A logic design system can help a logic designer design and test complex circuits for a system. When a design is complete, the logic design system may be used to generate configuration data for electrically programming the appropriate programmable logic device.

An illustrative logic circuit design system 300 in accordance with an embodiment is shown in FIG. 3 . If desired, circuit design system of FIG. 3 may be used in a logic design system such as logic design system 56 shown in FIG. 2 . Circuit design system 300 may be implemented on integrated circuit design computing equipment. For example, system 300 may be based on one or more processors such as personal computers, workstations, etc. The processor(s) may be linked using a network (e.g., a local or wide area network). Memory in these computers or external memory and storage devices such as internal and/or external hard disks may be used to store instructions and data.

Software-based components such as computer-aided design tools 320 and databases 330 reside on system 300. During operation, executable software such as the software of computer aided design tools 320 runs on the processor(s) of system 300. Databases 330 are used to store data for the operation of system 300. In general, software and data may be stored on non-transitory computer readable storage media (e.g., tangible computer readable storage media). The software code may sometimes be referred to as software, data, program instructions, instructions, or code. The non-transitory computer readable storage media may include computer memory chips, non-volatile memory such as non-volatile random-access memory (NVRAM), one or more hard drives (e.g., magnetic drives or solid state drives), one or more removable flash drives or other removable media, compact discs (CDs), digital versatile discs (DVDs), Blu-ray discs (BDs), other optical media, and floppy diskettes, tapes, or any other suitable memory or storage device(s).

Software stored on the non-transitory computer readable storage media may be executed on system 300. When the software of system 300 is installed, the storage of system 300 has instructions and data that cause the computing equipment in system 300 to execute various methods (processes). When performing these processes, the computing equipment is configured to implement the functions of circuit design system 300.

The computer aided design (CAD) tools 320, some or all of which are sometimes referred to collectively as a CAD tool, a circuit design tool, or an electronic design automation (EDA) tool, may be provided by a single vendor or by multiple vendors. Tools 320 may be provided as one or more suites of tools (e.g., a compiler suite for performing tasks associated with implementing a circuit design in a programmable logic device) and/or as one or more separate software components (tools). Database(s) 330 may include one or more databases that are accessed only by a particular tool or tools and may include one or more shared databases. Shared databases may be accessed by multiple tools. For example, a first tool may store data for a second tool in a shared database. The second tool may access the shared database to retrieve the data stored by the first tool. This allows one tool to pass information to another tool. Tools may also pass information between each other without storing information in a shared database if desired.

Illustrative computer aided design tools 420 that may be used in a circuit design system such as circuit design system 300 of FIG. 3 are shown in FIG. 4 .

The design process may start with the formulation of functional specifications of the integrated circuit design (e.g., a functional or behavioral description of the integrated circuit design). A circuit designer may specify the functional operation of a desired circuit design using design and constraint entry tools 464. Design and constraint entry tools 464 may include tools such as design and constraint entry aid 466 and design editor 468. Design and constraint entry aids such as aid 466 may be used to help a circuit designer locate a desired design from a library of existing circuit designs and may provide computer-aided assistance to the circuit designer for entering (specifying) the desired circuit design.

As an example, design and constraint entry aid 466 may be used to present screens of options for a user. The user may click on on-screen options to select whether the circuit being designed should have certain features. Design editor 468 may be used to enter a design (e.g., by entering lines of hardware description language code), may be used to edit a design obtained from a library (e.g., using a design and constraint entry aid), or may assist a user in selecting and editing appropriate prepackaged code/designs.

Design and constraint entry tools 464 may be used to allow a circuit designer to provide a desired circuit design using any suitable format. For example, design and constraint entry tools 464 may include tools that allow the circuit designer to enter a circuit design using truth tables. Truth tables may be specified using text files or timing diagrams and may be imported from a library. Truth table circuit design and constraint entry may be used for a portion of a large circuit or for an entire circuit.

As another example, design and constraint entry tools 464 may include a schematic capture tool. A schematic capture tool may allow the circuit designer to visually construct integrated circuit designs from constituent parts such as logic gates and groups of logic gates. Libraries of preexisting integrated circuit designs may be used to allow a desired portion of a design to be imported with the schematic capture tools.

If desired, design and constraint entry tools 464 may allow the circuit designer to provide a circuit design to the circuit design system 300 using a hardware description language such as Verilog hardware description language (Verilog HDL), Very High Speed Integrated Circuit Hardware Description Language (VHDL), System Verilog, or a higher-level circuit description language such as OpenCL or SystemC, just to name a few. The designer of the integrated circuit design can enter the circuit design by writing hardware description language code with editor 468. Blocks of code may be imported from user-maintained or commercial libraries if desired.

After the design has been entered using design and constraint entry tools 464, behavioral simulation tools 472 may be used to simulate the functionality of the circuit design. If the functionality of the design is incomplete or incorrect, the circuit designer can make changes to the circuit design using design and constraint entry tools 464. The functional operation of the new circuit design may be verified using behavioral simulation tools 472 before synthesis operations have been performed using tools 474. Simulation tools such as behavioral simulation tools 472 may also be used at other stages in the design flow if desired (e.g., after logic synthesis). The output of the behavioral simulation tools 472 may be provided to the circuit designer in any suitable format (e.g., truth tables, timing diagrams, etc.).

Once the functional operation of the circuit design has been determined to be satisfactory, logic synthesis and optimization tools 474 may generate a gate-level netlist of the circuit design, for example using gates from a particular library pertaining to a targeted process supported by a foundry, which has been selected to produce the integrated circuit. Alternatively, logic synthesis and optimization tools 474 may generate a gate-level netlist of the circuit design using gates of a targeted programmable logic device (i.e., in the logic and interconnect resources of a particular programmable logic device product or product family).

Logic synthesis and optimization tools 474 may optimize the design by making appropriate selections of hardware to implement different logic functions in the circuit design based on the circuit design data and constraint data entered by the logic designer using tools 464. As an example, logic synthesis and optimization tools 474 may perform multi-level logic optimization and technology mapping based on the length of a combinational path between registers in the circuit design and corresponding timing constraints that were entered by the logic designer using tools 464.

After logic synthesis and optimization using tools 474, the circuit design system may use tools such as placement, routing, and physical synthesis tools 476 to perform physical design steps (layout synthesis operations). Tools 476 can be used to determine where to place each gate of the gate-level netlist produced by tools 474. For example, if two counters interact with each other, tools 476 may locate these counters in adjacent regions to reduce interconnect delays or to satisfy timing requirements specifying the maximum permitted interconnect delay. Tools 476 create orderly and efficient implementations of circuit designs for any targeted integrated circuit (e.g., for a given programmable integrated circuit such as an FPGA).

Tools such as tools 474 and 476 may be part of a compiler suite (e.g., part of a suite of compiler tools provided by a programmable logic device vendor). In certain embodiments, tools such as tools 474, 476, and 478 may also include timing analysis tools such as timing estimators. This allows tools 474 and 476 to satisfy performance requirements (e.g., timing requirements) before actually producing the integrated circuit.

After an implementation of the desired circuit design has been generated using tools 476, the implementation of the design may be analyzed and tested using analysis tools 478. For example, analysis tools 478 may include timing analysis tools, power analysis tools, or formal verification tools, just to name few.

After satisfactory optimization operations have been completed using tools 420 and depending on the targeted integrated circuit technology, tools 420 may produce a mask-level layout description of the integrated circuit or configuration data for programming the programmable logic device.

Illustrative operations involved in using tools 420 of FIG. 4 to produce the mask-level layout description of the integrated circuit are shown in FIG. 5 . As shown in FIG. 5 , a circuit designer may first provide a design specification 502. The design specification 502 may, in general, be a behavioral description provided in the form of an application code (e.g., C code, C++ code, SystemC code, OpenCL code, etc.). In some scenarios, the design specification may be provided in the form of a register transfer level (RTL) description 506.

The RTL description may have any form of describing circuit functions at the register transfer level. For example, the RTL description may be provided using a hardware description language such as the Verilog hardware description language (Verilog HDL or Verilog), the SystemVerilog hardware description language (SystemVerilog HDL or System Verilog), or the Very High Speed Integrated Circuit Hardware Description Language (VHDL). If desired, a portion or all of the RTL description may be provided as a schematic representation or in the form of a code using OpenCL, MATLAB, Simulink, or other high-level synthesis (HLS) language.

In general, the behavioral design specification 502 may include untimed or partially timed functional code (i.e., the application code does not describe cycle-by-cycle hardware behavior), whereas the RTL description 506 may include a fully timed design description that details the cycle-by-cycle behavior of the circuit at the register transfer level.

Design specification 502 or RTL description 506 may also include target criteria such as area use, power consumption, delay minimization, clock frequency optimization, or any combination thereof. The optimization constraints and target criteria may be collectively referred to as constraints.

Those constraints can be provided for individual data paths, portions of individual data paths, portions of a design, or for the entire design. For example, the constraints may be provided with the design specification 502, the RTL description 506 (e.g., as a pragma or as an assertion), in a constraint file, or through user input (e.g., using the design and constraint entry tools 464 of FIG. 4 ), to name a few.

At step 504, behavioral synthesis (sometimes also referred to as algorithmic synthesis) may be performed to convert the behavioral description into an RTL description 506. Step 504 may be skipped if the design specification is already provided in form of an RTL description.

At step 518, behavioral simulation tools 472 may perform an RTL simulation of the RTL description, which may verify the functionality of the RTL description. If the functionality of the RTL description is incomplete or incorrect, the circuit designer can make changes to the HDL code (as an example). During RTL simulation 518, actual results obtained from simulating the behavior of the RTL description may be compared with expected results.

During step 508, logic synthesis operations may generate gate-level description 510 using logic synthesis and optimization tools 474 from FIG. 4 . The output of logic synthesis 508 is a gate-level description 510 of the design.

During step 512, placement operations using for example placement tools 476 of FIG. 4 may place the different gates in gate-level description 510 in a preferred location on the targeted integrated circuit to meet given target criteria (e.g., minimize area and maximize routing efficiency or minimize path delay and maximize clock frequency or minimize overlap between logic elements, or any combination thereof). The output of placement 512 is a placed gate-level description 513, which satisfies the legal placement constraints of the underlying target device.

During step 515, routing operations using for example routing tools 476 of FIG. 4 may connect the gates from the placed gate-level description 513. Routing operations may attempt to meet given target criteria (e.g., minimize congestion, minimize path delay and maximize clock frequency, satisfy minimum delay requirements, or any combination thereof). The output of routing 515 is a mask-level layout description 516 (sometimes referred to as routed gate-level description 516). The mask-level layout description 516 generated by the design flow of FIG. 5 may sometimes be referred to as a device configuration bit stream or a device configuration image.

While placement and routing is being performed at steps 512 and 515, physical synthesis operations 517 may be concurrently performed to further modify and optimize the circuit design (e.g., using physical synthesis tools 476 of FIG. 4 ).

Multi-Tenant Usage

In implementations of the disclosure, programmable integrated circuit device 10 may be configured using tools described in FIGS. 2-5 to support a multi-tenant usage model or scenario. As noted above, examples of programmable logic devices include programmable arrays logic (PALs), programmable logic arrays (PLAs), field programmable logic arrays (FPLAs), electrically programmable logic devices (EPLDs), electrically erasable programmable logic devices (EEPLDs), logic cell arrays (LCAs), complex programmable logic devices (CPLDs), and field programmable gate arrays (FPGAs), just to name a few. System configurations in which device 10 is a programmable logic device such as an FPGA is sometimes described as an example but is not intended to limit the scope of the present embodiments.

In accordance with an embodiment, FIG. 6 is a diagram of a multitenancy system such as system 600. As shown in FIG. 6 , system 600 may include at least a host platform provider 602 (e.g., a server, a cloud service provider or “CSP”), a programmable integrated circuit device 10 such as an FPGA, and multiple tenants 604 (sometimes referred to as “clients”). The CSP 602 may interact with FPGA 10 via communications path 680 and may, in parallel, interact with tenants 604 via communications path 682. The FPGA 10 may separately interact with tenants 604 via communications path 684. In a multitenant usage model, FPGA 10 may be provisioned by the CSP 602 to support each of various tenants/clients 604 running their own separate applications. It may be assumed that the tenants do not trust each other, that the clients do not trust the CSP, and that the CSP does not trust the tenants.

The FPGA 10 may include a security engine, such as a secure device manager (SDM) 650, that acts as a configuration manager and security enclave for the FPGA 10. The SDM 650 can conduct reconfiguration and security functions for the FPGA 10. For example, the SDM 650, can conduct functions including, but not limited to, sectorization, PUF key protection, key management, hard encrypt/authenticate engines, and zeroization. Additionally, environmental sensors (not shown) of the FPGA 10 that monitor voltage and temperature can be controlled by the SDM. Furthermore, device maintenance functions, such as secure return material authorization (RMA) without revealing encryption keys, secure debug of designs and ARM code, and secure key managed are additional functions enabled by the SDM 650.

Cloud service provider 602 may provide cloud services accelerated on one or more accelerator devices such as application-specific integrated circuits (ASICs), graphics processor units (GPUs), and FPGAs to multiple cloud customers (i.e., tenants). In the context of FPGA-as-a-service usage model, cloud service provider 602 may offload more than one workload to an FPGA 10 so that multiple tenant workloads may run simultaneously on the FPGA as different partial reconfiguration (PR) workloads. In such scenarios, FPGA 10 can provide security assurances and PR workload isolation when security-sensitive workloads (or payloads) are executed on the FPGA.

Cloud service provider 602 may define a multitenancy mode (MTM) sharing and allocation policy 610. The MTM sharing and allocation policy 610 may set forth a base configuration bitstream such as base static image 612, a partial reconfiguration region allowlist such as PR allowlist 614, peek and poke vectors 616, timing and energy constraints 618 (e.g., timing and power requirements for each potential tenant or the overall multitenant system), deterministic data assets 620 (e.g., a hash list of binary assets or other reproducible component that can be used to verify the proper loading of tenant workloads into each PR region), etc. Policy 610 is sometimes referred to as an FPGA multitenancy mode contract. One or more components of MTM sharing and allocation policy 610 such as the base static image 612, PR region allowlist 61, and peek/poke vectors 616 may be generated by the cloud service provider using design tools 420 of FIG. 4 .

The base static image 612 may define a base design for device 10 (see, e.g., FIG. 7 ). As shown in FIG. 7 , the base static image 612 may define the input-output interfaces 704, one or more static region(s) 702, and multiple partial reconfiguration (PR) regions each of which may be assigned to a respective tenant to support an isolated workload. Static region 702 may be a region where all parties agree that the configuration bits cannot be changed by partial reconfiguration. For example, static region may be owned by the server/host/CSP. Any resource on device 10 should be assigned either to static region 702 or one of the PR regions (but not both).

The PR region allowlist 614 may define a list of available PR regions 630 (see FIG. 6 ). Each PR region for housing a particular tenant may be referred to as a PR “sandbox,” in the sense of providing a trusted execution environment (TEE) for providing spatial/physical isolation and preventing potential undesired interference among the multiple tenants. Each PR sandbox may provide assurance that the contained PR tenant workload (sometimes referred to as the PR client persona) is limited to configured its designated subset of the FPGA fabric and is protected from access by other PR workloads. The precise allocation of the PR sandbox regions and the boundaries 660 of each PR sandbox may also be defined by the base static image. Additional reserved padding area such as area 706 in FIG. 7 may be used to avoid electrical interference and coupling effects such as crosstalk. Additional circuitry may also be formed in padding area 706 for actively detecting and/or compensating unwanted effects generated as a result of electrical interference, noise, or power surge. Any wires such as wires 662 crossing a PR sandbox boundary may be assigned to either an associated PR sandbox or to the static region 702. If a boundary-crossing wire 662 is assigned to a PR sandbox region, routing multiplexers outside that sandbox region controlling the wire should be marked as not to be used. If a boundary-cross wire 662 is assigned to the static region, the routing multiplexers inside that sandbox region controlling the wire should be marked as not belonging to that sandbox region (e.g., these routing multiplexers should be removed from a corresponding PR region mask).

Any hard (non-reconfigurable) embedded intellectual property (IP) blocks such as memory blocks (e.g., random-access memory blocks) or digital signal processing (DSP) blocks that are formed on FPGA 10 may also be assigned either to a PR sandbox or to the static region. In other words, any given hard IP functional block should be completely owned by a single entity (e.g., any fabric configuration for a respective embedded functional block is either allocated to a corresponding PR sandbox or the static region).

DISAGGREGATED COMPUTE IN PROGRAMMABLE INTEGRATED CIRCUITS

As previously described, disaggregated computing is on the rise in data centers. CSPs are deploying solutions where processing of a workload is distributed on disaggregated compute resources such as CPUs and hardware accelerators, such as FPGAs, that are connected via network instead of being on the same platform, connected via physical links such as PCIe. The compute disaggregation enables improved resource utilization and lowers Total Cost of Ownership (TCO) by enabling making more efficient use of available resources. Disaggregation also enables pooling a large number of hardware accelerators for large computation making the computation more efficient and performant.

Embodiments provide for a novel technique for disaggregated computing in programmable integrated circuits, such as the programmable logic devices described above with respect to FIGS. 1-7 . This novel technique is used to provide for the above-noted improved computation efficiency and performance in computing architectures seeking to implement disaggregate computing. Implementations of the disclosure provide enabling secure state-clean during configuration of PR bitstreams on programmable integrated circuits, as discussed further below with respect to FIGS. 8-15 .

FIG. 8 illustrates a computing device 800 employing a disaggregate compute component 810 according to one implementation of the disclosure. Computing device 800 represents a communication and data processing device including or representing (without limitations) smart voice command devices, intelligent personal assistants, home / office automation system, home appliances (e.g., washing machines, television sets, etc.), mobile devices (e.g., smartphones, tablet computers, etc.), gaming devices, handheld devices, wearable devices (e.g., smartwatches, smart bracelets, etc.), virtual reality (VR) devices, head — mounted display (HMDs), Internet of Things (IoT) devices, laptop computers, desktop computers, server computers, set — top boxes (e.g., Internet based cable television set — top boxes, etc.), global positioning system (GPS) — based devices, automotive infotainment devices, etc.

In some embodiments, computing device 800 includes or works with or is embedded in or facilitates any number and type of other smart devices, such as (without limitation) autonomous machines or artificially intelligent agents, such as a mechanical agents or machines, electronics agents or machines, virtual agents or machines, electromechanical agents or machines, etc. Examples of autonomous machines or artificially intelligent agents may include (without limitation) robots, autonomous vehicles (e.g., self-driving cars, self — flying planes, self — sailing boats, etc.), autonomous equipment self — operating construction vehicles, self — operating medical equipment, etc.), and / or the like. Further, “autonomous vehicles” are not limed to automobiles but that they may include any number and type of autonomous machines, such as robots, autonomous equipment, household autonomous devices, and / or the like, and any one or more tasks or operations relating to such autonomous machines may be interchangeably referenced with autonomous driving.

Further, for example, computing device 800 may include a computer platform hosting an integrated circuit (“IC”), such as a system on a chip (“SOC” or “SOC”), integrating various hardware and / or software components of computing device 800 on a single chip.

As illustrated, in one embodiment, computing device 800 may include any number and type of hardware and / or software components, such as (without limitation) graphics processing unit (“GPU” or simply “graphics processor”) 816, graphics driver (also referred to as “GPU driver”, “graphics driver logic”, “driver logic”, user — mode driver (UMD), user — mode driver framework (UMDF), or simply “driver ”) 815, central processing unit (“CPU” or simply “application processor”) 812, hardware accelerator 814 (such as programmable logic device 10 described above with respect to FIGS. 1-7 including, but not limited to, an FPGA, ASIC, a re-purposed CPU, or a re-purposed GPU, for example), memory 808, network devices, drivers, or the like, as well as input/output (I/O) sources 804, such as touchscreens, touch panels, touch pads, virtual or regular keyboards, virtual or regular mice, ports, connectors, etc. Computing device 800 may include operating system (OS) 806 serving as an interface between hardware and / or physical resources of the computing device 800 and a user.

It is to be appreciated that a lesser or more equipped system than the example described above may be utilized for certain implementations. Therefore, the configuration of computing device 800 may vary from implementation to implementation depending upon numerous factors, such as price constraints, performance requirements, technological improvements, or other circumstances.

Embodiments may be implemented as any or a combination of: one or more microchips or integrated circuits interconnected using a parent board, hardwired logic, software stored by a memory device and executed by a microprocessor, firmware, an application specific integrated circuit (ASIC), and / or a field programmable gate array (FPGA). The terms “logic”, “module”, “component”, “engine”, “circuitry”, “element”, and “mechanism” may include, by way of example, software, hardware and / or a combination thereof, such as firmware.

In one embodiment, as illustrated, disaggregate compute component 810 may be hosted by memory 808 in communication with I/O source(s) 804, such as microphones, speakers, etc., of computing device 800. In another embodiment, disaggregate compute component 810 may be part of or hosted by operating system 806. In yet another embodiment, disaggregate compute component 810 may be hosted or facilitated by graphics driver 815. In yet another embodiment, disaggregate compute component 810 may be hosted by or part of a hardware accelerator 814; for example, disaggregate compute component 810 may be embedded in or implemented as part of the processing hardware of hardware accelerator 814, such as in the form of disaggregate compute component 840. In yet another embodiment, disaggregate compute component 810 may be hosted by or part of graphics processing unit (“GPU” or simply graphics processor”) 816 or firmware of graphics processor 816; for example, disaggregate compute component may be embedded in or implemented as part of the processing hardware of graphics processor 816, such as in the form of disaggregate compute component 830. Similarly, in yet another embodiment, disaggregate compute evaluation component 810 may be hosted by or part of central processing unit (“CPU” or simply “application processor”) 812; for example, disaggregate compute evaluation component 820 may be embedded in or implemented as part of the processing hardware of application processor 812, such as in the form of disaggregate compute component 820. In some embodiments, disaggregate compute component 810 may be provided by one or more processors including one or more of a graphics processor, an application processor, and another processor, wherein the one or more processors are co-located on a common semiconductor package.

It is contemplated that embodiments are not limited to certain implementation or hosting of disaggregate compute component 810 and that one or more portions or components of disaggregate compute component 810 may be employed or implemented as hardware, software, or any combination thereof, such as firmware. In one embodiment, for example, the disaggregate compute component may be hosted by a machine learning processing unit which is different from the GPU. In another embodiment, the disaggregate compute component may be distributed between a machine learning processing unit and a CPU. In another embodiment, the disaggregate compute component may be distributed between a machine learning processing unit, a CPU and a GPU. In another embodiment, the disaggregate compute component may be distributed between a machine learning processing unit, a CPU, a GPU, and a hardware accelerator.

Computing device 800 may host network interface device(s) to provide access to a network, such as a LAN, a wide area network (WAN), a metropolitan area network (MAN), a personal area network (PAN), Bluetooth, a cloud network, a mobile network (e.g., 3rd Generation (3G), 4th Generation (4G), etc.), an intranet, the Internet, etc. Network interface(s) may include, for example, a wireless network interface having antenna, which may represent one or more antenna(s). Network interface(s) may also include, for example, a wired network interface to communicate with remote devices via network cable, which may be, for example, an Ethernet cable, a coaxial cable, a fiber optic cable, a serial cable, or a parallel cable.

Embodiments may be provided, for example, as a computer program product which may include one or more machine - readable media having stored thereon machine executable instructions that, when executed by one or more machines such as a computer, network of computers, or other electronic devices, may result in the one or more machines carrying out operations in accordance with embodiments described herein. A machine — readable medium may include, but is not limited to, floppy diskettes, optical disks, CD — ROMs (Compact Disc — Read Only Memories), and magneto — optical disks, ROMs, RAMS, EPROMs (Erasable Programmable Read Only Memories), EEPROMs (Electrically Erasable Programmable Read Only Memories), magnetic or optical cards, flash memory, or other type of media / machine — readable medium suitable for storing machine — executable instructions.

Moreover, embodiments may be downloaded as a computer program product, wherein the program may be transferred from a remote computer (e.g., a server) to a requesting computer (e.g., a client) by way of one or more data signals embodied in and /or modulated by a carrier wave or other propagation medium via a communication link (e.g., a modem and / or network connection).

Throughout the document, term “user” may be interchangeably referred to as “viewer”, “observer”, “speaker”, “person”, “individual”, “end – user”, and / or the like. It is to be noted that throughout this document, terms like “graphics domain” may be referenced interchangeably with “graphics processing unit”, “graphics processor”, or simply “GPU” and similarly, “CPU domain” or “host domain” may be referenced interchangeably with “computer processing unit”, “application processor”, or simply “CPU”.

It is to be noted that terms like “node”, “computing node”, “server”, “server device”, “cloud computer”, “cloud server”, “cloud server computer”, “machine”, “host machine”, “device”, “computing device”, “computer”, “computing system”, and the like, may be used interchangeably throughout this document. It is to be further noted that terms like “application”, “software application”, “program”, “software program”, “package”, “software package”, and the like, may be used interchangeably throughout this document. Also, terms like “job”, “input”, “request”, “message ”, and the like, may be used interchangeably throughout this document.

FIG. 9 illustrates disaggregate compute component 810 of FIG. 8 , according to one implementation of the disclosure. For brevity, many of the details already discussed with reference to FIG. 8 are not repeated or discussed hereafter. In one embodiment, disaggregate compute component 810 may be the same as any of disaggregate compute components 810, 820, 830, 840 described with respect to FIG. 8 and may include any number and type of components, such as (without limitations): secure state-clean component 902.

Computing device 800 is further shown to include user interface 919 (e.g., graphical user interface (GUI) based user interface, Web browser, cloud-based platform user interface, software application-based user interface, other user or application programming interfaces (APIs), etc.). Computing device 800 may further include I/O source(s) 804 having input component (s) 931, such as camera(s) 942 (e.g., Intel® RealSenseTM camera), sensors, microphone(s) 941, etc., and output component(s) 933, such as display device(s) or simply display(s) 944 (e.g., integral displays, tensor displays, projection screens, display screens, etc.), speaker devices(s) or simply speaker(s), etc.

Computing device 800 is further illustrated as having access to and/or being in communication with one or more database(s) 925 and/or one or more of other computing devices over one or more communication medium(s) 930 (e.g., networks such as a proximity network, a cloud network, the Internet, etc.).

In some embodiments, database(s) 925 may include one or more of storage mediums or devices, repositories, data sources, etc., having any amount and type of information, such as data, metadata, etc., relating to any number and type of applications, such as data and/or metadata relating to one or more users, physical locations or areas, applicable laws, policies and/or regulations, user preferences and/or profiles, security and/or authentication data, historical and/or other details, and/or the like.

As aforementioned, computing device 800 may host I/O sources 804 including input component(s) 931 and output component(s) 933. In one embodiment, input component(s) 931 may include a sensor array including, but not limited to, microphone(s) 941 (e.g., ultrasound microphones), camera(s) 942 (e.g., two-dimensional (2D) cameras, three — dimensional (3D) cameras, infrared (IR) cameras, depth-sensing cameras, etc.), capacitors, radio components, radar components, scanners, and/or accelerometers, etc. Similarly, output component(s) 933 may include any number and type of display device(s) 944, projectors, light — emitting diodes (LEDs), speaker(s) 943, and / or vibration motors, etc.

As aforementioned, terms like “logic”, “module”, “component”, “engine”, “circuitry”, “element”, and “mechanism” may include, by way of example, software or hardware and / or a combination thereof, such as firmware. For example, logic may itself be or include or be associated with circuitry at one or more devices, such as disaggregate compute component 820, disaggregate compute component 830, and/or disaggregate compute component 840 hosted by application processor 812, graphics processor 816, and/or hardware accelerator 814, respectively, of FIG. 8 having to facilitate or execute the corresponding logic to perform certain tasks.

For example, as illustrated, input component (s) 931 may include any number and type of microphone(s) 941, such as multiple microphones or a microphone array, such as ultrasound microphones, dynamic microphones, fiber optic microphones, laser microphones, etc. It is contemplated that one or more of microphone(s) 941 serve as one or more input devices for accepting or receiving audio inputs ( such as human voice ) into computing device 800 and converting this audio or sound into electrical signals . Similarly, it is contemplated that one or more of camera(s) 942 serve as one or more input devices for detecting and capturing of image and / or videos of scenes, objects, etc., and provide the captured data as video inputs into computing device 800.

As previously described, disaggregated computing is on the rise in data centers. CSPs are deploying solutions where processing of a workload is distributed on disaggregated compute resources such as CPUs and hardware accelerators, such as FPGAs, that are connected via network instead of being on the same platform, connected via physical links such as PCIe. The compute disaggregation enables improved resource utilization and lowers Total Cost of Ownership (TCO) by enabling making more efficient use of available resources. Disaggregation also enables pooling a large number of hardware accelerators for large computation making the computation more efficient and performant.

Embodiments provide for a novel technique for disaggregate computing for distributed confidential computing environments. This novel technique is used to provide for the above-noted improved computation efficiency and performance in computing architectures seeking to implement disaggregate computing. Implementations of the disclosure utilize a disaggregate compute component 810 to provide enabling stateless accelerator designs shared across mutually distrustful tenants, provide enabling secure state-clean during configuration of PR bitstreams on programmable integrated circuits, provide runtime fault detection, location and circuit recovery, provide enabling secure communication via attestation of multi-tenant configurations on cloud FPGAs, provide transparent NoC access control for spatial FPGA multitenancy, provide broadcast remote sealing for scalable TEE provisioning, provide enabling late-binding of security features via configuration security controller for cloud FPGAs, and/or provide scalable runtime validation for on-device design rule checks.

With respect to FIG. 9 , the disaggregate compute component 810 includes secure state-clean component 902 to perform the disaggregated computing for programmable integrated circuits of the disaggregate compute component 810 described herein. Further details of secure state-clean component 902 are described below with respect to FIGS. 10-15 .

ENABLING SECURE STATE-CLEAN DURING CONFIGURATION OF PR BITSTREAMS ON PROGRAMMABLE INTEGRATED CIRCUITS

In some embodiments, an apparatus, system, or process is to provide secure state-clean during configuration of PR bitstreams on programmable logic devices, such as FPGAs. In one implementation, secure state-clean component 902 described with respect to FIG. 9 provides secure state-clean during configuration of PR bitstreams on programmable logic devices.

Cloud Service Providers (CSP) deliver resources such as networks, data, storage, devices as part of Infrastructure as a Service (IaaS) which are managed by the end-users or CSP customers. FIG. 10 illustrates a network environment 1000 implementing an Infrastructure-as-a-Service (IaaS) usage model having secure-state leaking across mutually-distrustful tenants. In the IaaS usage model depicted in network environment 1000, a Cloud Service Provider (CSP) 1010 hosts an ML/AI service, such as an ML/AI-based image classification service. The ML/AI service may have corresponding DNN model/weights 1055 maintained by a CPU 1050 of a server device 1020 in communication with a memory 1030, such as a dual data-rate (DDR) memory module. The ML/AI service hosted by CSP 1010 may offload inferencing to an accelerator device, such as FPGA 1040 on FPGA card 1025, hosted in the CSP 1010 for performance benefits.

In implementations of the disclosure, an FPGA 1040 is specifically discussed. However, any type of hardware accelerator device and/or programmable logic integrated circuit (IC) (also referred to as a programmable IC) may utilize implementations of the disclosure and implements are not specifically limited to utilization in an FPGA environment. Examples of programmable logic ICs include programmable arrays logic (PALs), programmable logic arrays (PLAs), field programmable logic arrays (FPLAs), electrically programmable logic devices (EPLDs), electrically erasable programmable logic devices (EEPLDs), logic cell arrays (LCAs), complex programmable logic devices (CPLDs), and field programmable gate arrays (FPGAs), just to name a few. However, for ease of discussion and illustration, the specific example of an FPGA is described herein.

For ease of explanation, the accelerator device is considered to be an FPGA 1040 for following description purposes. In some implementations, the FPGA 1040 may include a management region 1042 managing link, protocol, PHY, memory controller, security, and so on. In the case of AI/ML analytics for an image classification usage, an offloaded PR bitstream configured on the FPGA 1040 may be an inference engine 1044 for the AI/ML analytics (e.g., inference engine for image classification). In some implementations, FPGA 1040 also includes a security engine 1046 (e.g., such as SDM 650 described with respect to FIG. 6 ).

A CSP’s 1010 customer (also referred to as a partial reconfiguration (PR) tenant or tenant, such as PR tenant 1 1001 and/or PR tenant 2 1003) is an entity that requests to use the CSP-hosted service based on an agreement with the CSP 1010. As shown in FIG. 10 , the PR tenants, including PR tenant 1 (PR1) 1001 and PR tenant 2 (PR2) 1003, provide PR bitstreams, that can include PR1 bitstream 1002 and/or PR2 bitstream 1004 via a communication medium 1005 (such as a network). The provided PR1 bitstream 1002 and/or PR2 bitstream 1004 is processed by the ML/AI service hosted by CSP 1010 to configure at least a portion of FPGA 1040.

In some implementations, the CSP 1010 may support multiple CSP customers in a time-sliced fashion or a temporal multi-tenant scenario sharing the same offloaded kernel configured and/or integrated on accelerator device (e.g., FPGA 1040). For example, if the accelerator device is a reconfigurable logic device, such as an FPGA 1040, then the CSP 1010 can dynamically reconfigure a portion of the FPGA 1040 logic via Partial Reconfiguration (PR) for use by a particular PR tenant (such as PR1 1001 or PR2 1003), while the rest of the FPGA logic remains unaffected or powered down. As such, it can be envisioned that in a given FPGA 1040 life-cycle, there may more than one PR bitstream that is reconfigured over the same FPGA 1040 device as part of a CSP-hosted service. The term PR bitstream owner may also be referred to as a PR tenant (e.g., PR1 1001 or PR2 1003). Based on the usage or deployment, the PR tenant may be the CSP 1010 or a third-party, as in case of Firmware-as-a-Service (FaaS) models.

A technical problem associated with the IaaS usage model depicted in network environment 1000 is that there are no existing mechanisms that guarantee that the PR tenant’s (e.g., PR1 1001, PR2 1003) secure state is not leaked across PR tenant transitions. As previously noted, in the case of AI/ML analytics for an image classification usage, the offloaded PR bitstream to the FPGA 1040 may be an inference engine 1044. The offloaded logic (e.g., inference engine 1044) is treated as an asset with proprietary weights and biases associated to the model (e.g., DNN model/weights 1055) used for inference operations. As such, the PR tenant may allow the CSP 1010 to use the PR bitstream, but the PR tenant does not have to trust the CSP 1010. The PR tenant could encrypt the PR bitstream via existing bitstream encryption techniques, such that the CSP 1010 could deploy the PR bitstream but not access the PR bitstream logic in FPGA 1040.

In the above-discussed CSP-defined usage model, the PR tenants (e.g., PR1 1001, PR2 1003) (if there are more than one) are mutually distrustful. For example, a malicious PR tenant could craft a PR bitstream that can steal security-sensitive state associated to the previously-loaded PR tenant’s bitstream. As such, providing security assurance during PR configuration that any existing PR bitstream is cleared before configuring a new PR bitstream to mitigate state-leaking across PR bitstreams would be beneficial.

Implementations of the disclosure describe a PR configuration flow that provides an implicit state clean of a current PR region as part of configuring a new PR bitstream. FIG. 11 illustrates a network environment 1100 implementing a PR configuration flow for secure state clean of an accelerator device, in accordance with implementations of the disclosure. Network environment 1100 include an accelerator device, such as FPGA 1110. In some implementations, the accelerator device could be a GPU, a re-purposed GPU, a re-purposed CPU, an ASIC, or an FPGA 1110, to name a few examples. In one implementation, FPGA 1110 is the same as FPGA 10 described above with respect to FIGS. 1-7 .

Implementations of the disclosure provide for a security profile to support PR state clean properties in FPGAs. In some implementations, SDM 650 of FPGA 10 may provide for and enable the security profile of implementations of the disclosure. The FPGA 1110 implements PR configuration 1115 to perform a PR configuration flow of implementations of the disclosure. Upon receiving a new PR persona 1120 for configuration via a new PR bitstream in FPGA 1110, the PR configuration 1115 performs a verified CLEAR operation 1140 to clear any previous PR bitstream’s residual state, such as to clear a current PR persona 1130. As previously discussed, a PR persona may refer to a PR tenant workload that is configured for a tenant into a PR region of the FPGA 1110. Subsequently, the PR configuration 1115 performs a verified SET operation 1150 associated with a new PR tenant, in order to configure the new PR bitstream for the new PR persons 1120.

FIG. 12 illustrates an FPGA fabric 1200 for implementing PR ownership regions, in accordance with implementations of the disclosure. In one implementations, FPGA fabric 1200 may be implemented as part of FPGA 1110 described with respect to FIG. 11 .

In some implementations, ownership for a region of the FPGA fabric 1200 is defined in a base configuration 1202 via region-ownership masks created for the region. The base configuration 1202 defines the static ownership 1203 of the CSP, which defines the PR configuration grid and defines the number and sizes of the different spatially located PR regions 1204. PR region ownership masks 1210, 1220, 1230, 1240, 1250 are masks that are defined for a given PR region defined in the case configuration 1202. As shown in one example, the PR regions 1204 include PR masks for PR region 1 ownership 1210, PR region 2 ownership 1220, PR region 3 ownership 1230, PR region 4 ownership 1240, and PR region 5 ownership 1250.

FIG. 13 illustrates a conventional PR configuration flow 1300 for an accelerator device, in accordance with implementations of the disclosure. The conventional PR configuration flow 1300 is a sequence of a non-secret and secret steps 1370 that Set or Clear configuration bits on masks 1360 of the FPGA fabric. In implementations of the disclosure, changing the PR persona 1350 (e.g., configuring using a new PR bitstream) of a PR region 1341, 1342, 1343, 1344, 1345 utilizes multiple steps to avoid electrical issues and properly change the persona. Changes are done by setting or clearing configuration bits. In the conventional PR configuration flow 1300, each mask 1360 is associated with a corresponding PR step 1370 for either setting or clearing the configuration bits. The PR steps 1370 with a solid oval boundary are set configuration bit steps, while the PR steps 1370 with a dashed oval boundary are clear configuration bit steps.

For example, the set configuration bit PR steps 1370 include, but are not limited to, F (set R_NRAM) 1321 corresponding to mask 2: R_NRAM 1301, G (set M20K_FRZLOGIC) 1322 corresponding to mask 3: M20K_FRZLOGIC 1302, H (Freeze) 1323 corresponding to mask 4: FREEZE 1303, J (set MMUX_CO/TMUX) 1325 corresponding to mask 6: MMUX_CO_TMUX 1305, L (set LATCHOFF) 1327 corresponding to mask 8: LATCHOFF 1307, N (set PRECFG) 1329 corresponding to mask 10: PRECFG 1309, Q (set PR_PERSONA) 1332 corresponding to mask 11: SET 1312, S (load ERAM) 1334 corresponding to mask 13: ERAM 1314, and W (set ROWCLK_FRZLOGIC) 1338 corresponding to mask 16: ROWCLK FRZLOGIC_SET 1318.

The clear configuration bit PR steps 1370 include, but are not limited to, I (clear MMUX_c1) 1324 corresponding to mask 5: MMUX_C1 1304, K (clear ROWCLK_FRZLOGIC )1326 corresponding to mask 7: ROWCLKFRZLOGIC 1306, M (clear PR Region) 1328 corresponding to mask 9: CLEAR 1308, O (clear LATCHOFF) 1330 corresponding to mask 8: LATCHOFF 1310, P (clear PRECFG) 1331 corresponding to mask 10: PRECFG 1311, R (clear MUX _CO/TMUX) 1333 corresponding to mask 12: MUX_CO_TMUX_PERSONA_CLEAR 1313, T (Unfreeze) 1335 corresponding to mask 14: UNFREEZE 1315, U (clear M20K_FRZLOGIC) 1336 corresponding to mask 3: M20K_FRZLOGIC 1316, and V (clear R NRAM) 1337 corresponding to mask 15: R_NRAM _CLEAR 1317.

As illustrated in conventional PR configuration flow 1300, some changes are PR region specific and contain no secrets. For example, the masks 1360 having a solid line boundary box are persona-independent (non-secret) masks. The persona-independent (non-secret) masks may include, but are not limited to, 2: R_NAM 1301, 2: M20K_FRZLOGIC 1302, 4: FREEZE 1303, 5: MMUX_C1 1304, 6: MMUX_C0_TMUX 1305, 7: ROWCLK FRZLOGIC 1306, 8: LATCHOFF 1308, 9: CLEAR 1308, 10: PRECFG 1309, 8: LATCHOFF 1310, 10: PRECFG 1311, and 3: M20K_FRZLOGIC 1316. These persona-independent masks can be exposed and can be publicly authenticated. Furthermore, these persona-independent masks are the PR region ownership masks that are independent of the PR persona 1350 or PR bitstream that is provided by a PR tenant.

However, some changes are PR persona dependent and contain secrets. These masks 1360 cannot be exposed. For example, in the conventional PR configuration flow 1300 shown in FIG. 13 , the masks 1360 having a dashed line boundary box are persona-dependent (secret) masks. The persona-dependent (secret) masks may include, but are not limited to, 12: MUX_CO_TMUX_PERSONA_CLEAR 1313, 13: ERAM 1314, 14: UNFREEZE 1315, 15: R_NRAM_CLEAR 1317, and 16: ROWCLKFRZLOGIC_SET 1318. These persona-dependent (secret) masks are PR persona 1350 specific and contain secrets.

In the conventional PR configuration flow 1300, a carefully-crafted malicious bitstream could steal a previous PR tenant’s bitstream residual state as the ERAM clear operation, shown with clear configuration bit PR step S 1334 for mask 13: ERAM 1314 is not explicitly performed before the set configuration bit PR step Q1332 for mask 11: SET 1312 of the new PR persona. As such, if the new PR bitstream is set to an empty bitstream capable of replaying the previously-set persona configuration bits, then there may be a secure state-leak across PR tenant transitions in the conventional approaches for configuration of accelerator devices.

FIG. 14 illustrates a PR configuration flow 1400 for secure state clean of an accelerator device, in accordance with implementations of the disclosure. In one implementation, PR configuration flow 1400 may be performed by FPGA 1110 described with respect to FIG. 11 . In some implementations, a security engine (e.g., security engine 1046 of FPGA 10) may provide the PR configuration flow 1400.

Implementations of the disclosure provide for modifying the PR configuration flow to perform a clear configuration bit PR step as part of the persona-independent masks 1410 that could be publicly authenticated. For example, in the conventional PR configuration flow 1300 of FIG. 13 , PR step K 1326 clears adaptive logic module (ALM) flip flops (FFs) (e.g., 7: ROWCLK FRZLOGIC mask 1306) and PR step M 1328 clears lookup table (LUT) RAMs (e.g., 9: CLEAR 1308), but there is no explicit step in configuration flow 1300 to clear the M20Ks.

As shown in the updated PR configuration flow 1400 of FIG. 14 , implementations of the disclosure introduce an additional PR step S 1435 to clear the M20Ks by loading the ERAM 1430 with zeroes. As shown in PR configuration flow 1400, implementations of the disclosure further change the persona-independent mask 1410 to a persona-dependent mask 1420 for clearing 1336 M20K Frzlogic 1316 (after PR step T 1335 for 14: UNFREEZE mask 1315).

Implementations of the disclosure discussed above are based on a CLEAR-before-SET concept that could be generically applicable to any FPGA PR configuration. Implementations of the disclosure provide for security properties using Persona-Independent mask operations that are not under adversary (e.g., malicious PR Tenant) control.

FIG. 15 is a flow diagram illustrating a method 1500 for enabling secure state-clean during configuration of partial reconfiguration bitstreams on FPGA, in accordance with implementations of the disclosure. Method 1500 may be performed by processing logic that may comprise hardware (e.g., circuitry, dedicated logic, programmable logic, etc.), software (such as instructions run on a processing device), or a combination thereof. More particularly, the method 1500 may be implemented in one or more modules as a set of logic instructions stored in a machine- or computer-readable storage medium such as RAM, ROM, PROM, firmware, flash memory, etc., in configurable logic such as, for example, programmable logic arrays (PLAs), field-programmable gate arrays (FPGAs), complex programmable logic devices (CPLDs), in fixed-functionality logic hardware using circuit technology such as, for example, application-specific integrated circuit (ASIC), complementary metal oxide semiconductor (CMOS) or transistor-transistor logic (TTL) technology, or any combination thereof.

The process of method 1500 is illustrated in linear sequences for brevity and clarity in presentation; however, it is contemplated that any number of them can be performed in parallel, asynchronously, or in different orders. Further, for brevity, clarity, and ease of understanding, many of the components and processes described with respect to FIGS. 10-14 may not be repeated or discussed hereafter. In one implementation, an accelerator device, such as FPGA 1110 described with respect to FIG. 11 , may perform method 1500.

Method 1500 begins at block 1510 where the accelerator device may receive an incoming partial reconfiguration (PR) bitstream corresponding to a new PR persona to configure a region of the accelerator device. At block 1520, the accelerator device may perform, as part of a PR configuration sequence for the new PR persona, a first clear operation to clear previously-set persona configuration bits in the region of the accelerator device.

Subsequently, at block 1530, the accelerator device may perform, as part of the PR configuration sequence subsequent to the first clear operation, a set operation to set new persona configuration bits in the region of the accelerator device. Lastly, at block 1540, the accelerator device may perform, as part of the PR configuration sequence, a second clear operation to clear memory blocks of the region that became unfrozen subsequent to the set operation. In one implementation, the second clear operation is performed using a persona-dependent mask corresponding to the new PR persona

Flowcharts representative of example hardware logic, machine readable instructions, hardware implemented state machines, and/or any combination thereof for implementing the systems, already discussed. The machine readable instructions may be one or more executable programs or portion(s) of an executable program for execution by a computer processor. The program may be embodied in software stored on a non-transitory computer readable storage medium such as a CD-ROM, a floppy disk, a hard drive, a DVD, a Blu-ray disk, or a memory associated with the processor, but the whole program and/or parts thereof could alternatively be executed by a device other than the processor and/or embodied in firmware or dedicated hardware. Further, although the example program is described with reference to the flowcharts illustrated in the various figures herein, many other methods of implementing the example computing system may alternatively be used. For example, the order of execution of the blocks may be changed, and/or some of the blocks described may be changed, eliminated, or combined. Additionally, or alternatively, any or all of the blocks may be implemented by one or more hardware circuits (e.g., discrete and/or integrated analog and/or digital circuitry, an FPGA, an ASIC, a comparator, an operational-amplifier (op-amp), a logic circuit, etc.) structured to perform the corresponding operation without executing software or firmware.

The machine readable instructions described herein may be stored in one or more of a compressed format, an encrypted format, a fragmented format, a compiled format, an executable format, a packaged format, etc. Machine readable instructions as described herein may be stored as data (e.g., portions of instructions, code, representations of code, etc.) that may be utilized to create, manufacture, and/or produce machine executable instructions. For example, the machine readable instructions may be fragmented and stored on one or more storage devices and/or computing devices (e.g., servers). The machine readable instructions may utilize one or more of installation, modification, adaptation, updating, combining, supplementing, configuring, decryption, decompression, unpacking, distribution, reassignment, compilation, etc. in order to make them directly readable, interpretable, and/or executable by a computing device and/or other machine. For example, the machine readable instructions may be stored in multiple parts, which are individually compressed, encrypted, and stored on separate computing devices, wherein the parts when decrypted, decompressed, and combined form a set of executable instructions that implement a program such as that described herein.

In another example, the machine readable instructions may be stored in a state in which they may be read by a computer, but utilize addition of a library (e.g., a dynamic link library (DLL)), a software development kit (SDK), an application programming interface (API), etc. in order to execute the instructions on a particular computing device or other device. In another example, the machine readable instructions may be configured (e.g., settings stored, data input, network addresses recorded, etc.) before the machine readable instructions and/or the corresponding program(s) can be executed in whole or in part. Thus, the disclosed machine readable instructions and/or corresponding program(s) are intended to encompass such machine readable instructions and/or program(s) regardless of the particular format or state of the machine readable instructions and/or program(s) when stored or otherwise at rest or in transit.

The machine readable instructions described herein can be represented by any past, present, or future instruction language, scripting language, programming language, etc. For example, the machine readable instructions may be represented using any of the following languages: C, C++, Java, C#, Perl, Python, JavaScript, HyperText Markup Language (HTML), Structured Query Language (SQL), Swift, etc.

As mentioned above, the example processes of FIGS. 5 and/or 6 may be implemented using executable instructions (e.g., computer and/or machine readable instructions) stored on a non-transitory computer and/or machine readable medium such as a hard disk drive, a flash memory, a read-only memory, a compact disk, a digital versatile disk, a cache, a random-access memory and/or any other storage device or storage disk in which information is stored for any duration (e.g., for extended time periods, permanently, for brief instances, for temporarily buffering, and/or for caching of the information). As used herein, the term non-transitory computer readable medium is expressly defined to include any type of computer readable storage device and/or storage disk and to exclude propagating signals and to exclude transmission media.

“Including” and “comprising” (and all forms and tenses thereof) are used herein to be open ended terms. Thus, whenever a claim employs any form of “include” or “comprise” (e.g., comprises, includes, comprising, including, having, etc.) as a preamble or within a claim recitation of any kind, it is to be understood that additional elements, terms, etc. may be present without falling outside the scope of the corresponding claim or recitation. As used herein, when the phrase “at least” is used as the transition term in, for example, a preamble of a claim, it is open-ended in the same manner as the term “comprising” and “including” are open ended.

The term “and/or” when used, for example, in a form such as A, B, and/or C refers to any combination or subset of A, B, C such as (1) A alone, (2) B alone, (3) C alone, (4) A with B, (5) A with C, (6) B with C, and (7) A with B and with C. As used herein in the context of describing structures, components, items, objects and/or things, the phrase “at least one of A and B” is intended to refer to implementations including any of (1) at least one A, (2) at least one B, and (3) at least one A and at least one B. Similarly, as used herein in the context of describing structures, components, items, objects and/or things, the phrase “at least one of A or B” is intended to refer to implementations including any of (1) at least one A, (2) at least one B, and (3) at least one A and at least one B. As used herein in the context of describing the performance or execution of processes, instructions, actions, activities and/or steps, the phrase “at least one of A and B” is intended to refer to implementations including any of (1) at least one A, (2) at least one B, and (3) at least one A and at least one B. Similarly, as used herein in the context of describing the performance or execution of processes, instructions, actions, activities and/or steps, the phrase “at least one of A or B” is intended to refer to implementations including any of (1) at least one A, (2) at least one B, and (3) at least one A and at least one B.

As used herein, singular references (e.g., “a”, “an”, “first”, “second”, etc.) do not exclude a plurality. The term “a” or “an” entity, as used herein, refers to one or more of that entity. The terms “a” (or “an”), “one or more”, and “at least one” can be used interchangeably herein. Furthermore, although individually listed, a plurality of means, elements or method actions may be implemented by, e.g., a single unit or processor. Additionally, although individual features may be included in different examples or claims, these may possibly be combined, and the inclusion in different examples or claims does not imply that a combination of features is not feasible and/or advantageous.

Descriptors “first,” “second,” “third,” etc. are used herein when identifying multiple elements or components which may be referred to separately. Unless otherwise specified or understood based on their context of use, such descriptors are not intended to impute any meaning of priority, physical order or arrangement in a list, or ordering in time but are merely used as labels for referring to multiple elements or components separately for ease of understanding the disclosed examples. In some examples, the descriptor “first” may be used to refer to an element in the detailed description, while the same element may be referred to in a claim with a different descriptor such as “second” or “third.” In such instances, it should be understood that such descriptors are used merely for ease of referencing multiple elements or components.

The following examples pertain to further embodiments. Example 1 is an apparatus to facilitate enabling secure state-clean during configuration of partial reconfiguration bitstreams on accelerator devices. The apparatus of Example 1 comprises a security engine to: receive an incoming partial reconfiguration (PR) bitstream corresponding to a new PR persona to configure a region of the apparatus; perform, as part of a PR configuration sequence for the new PR persona, a first clear operation to clear previously-set persona configuration bits in the region; perform, as part of the PR configuration sequence subsequent to the first clear operation, a set operation to set new persona configuration bits in the region; and perform, as part of the PR configuration sequence, a second clear operation to clear memory blocks of the region that became unfrozen subsequent to the set operation, the second clear operation performed using a persona-dependent mask corresponding to the new PR persona.

In Example 2, the subject matter of Example 1 can optionally include wherein the security engine comprises a configuration manager and security enclave for the apparatus. In Example 3, the subject matter of any one of Examples 1-2 can optionally include wherein the first clear operation is performed using a persona-independent mask that is publicly authenticated. In Example 4, the subject matter of any one of Examples 1-3 can optionally include wherein the persona-independent mask is not under control of a tenant of the apparatus.

In Example 5, the subject matter of any one of Examples 1-4 can optionally include wherein the second clear operation is performed by loading the memory blocks with zeros. In Example 6, the subject matter of any one of Examples 1-5 can optionally include wherein the new PR persona comprises a PR bitstream used to configure the region. In Example 7, the subject matter of any one of Examples 1-6 can optionally include wherein the apparatus comprises a hardware accelerator device comprising a programmable integrated circuit (IC). In Example 8, the subject matter of any one of Examples 1-7 can optionally include wherein the programmable IC comprises at least one of a field programmable gate array (FPGA), a programmable array logic (PAL), a programmable logic array (PLA), a field programmable logic array (FPLA), an electrically programmable logic device (EPLD), an electrically erasable programmable logic device (EEPLD), a logic cell array (LCA), or a complex programmable logic devices (CPLD).

Example 9 is a method for facilitating enabling secure communication via attestation of multi-tenant configuration on accelerator devices. The method of Example 9 can include receiving, by a programmable integrated circuit (IC), an incoming partial reconfiguration (PR) bitstream corresponding to a new PR persona to configure a region of the apparatus; performing, as part of a PR configuration sequence for the new PR persona, a first clear operation to clear previously-set persona configuration bits in the region; performing, as part of the PR configuration sequence subsequent to the first clear operation, a set operation to set new persona configuration bits in the region; and performing, as part of the PR configuration sequence, a second clear operation to clear memory blocks of the region that became unfrozen subsequent to the set operation, the second clear operation performed using a persona-dependent mask corresponding to the new PR persona.

In Example 10, the subject matter of Example 9 can optionally include wherein the security engine comprises a configuration manager and security enclave for the apparatus. In Example 11, the subject matter of any one of Examples 9-10 can optionally include wherein the first clear operation is performed using a persona-independent mask that is publicly authenticated, and wherein the persona-independent mask is not under control of a tenant of the apparatus. In Example 12, the subject matter of any one of Examples 9-11 can optionally include wherein the second clear operation is performed by loading the memory blocks with zeros.

In Example 13, the subject matter of any one of Examples 9-12 can optionally include wherein the new PR persona comprises a PR bitstream used to configure the region. In Example 14, the subject matter of any one of Examples 9-13 can optionally include wherein the programmable IC comprises at least one of a field programmable gate array (FPGA), a programmable array logic (PAL), a programmable logic array (PLA), a field programmable logic array (FPLA), an electrically programmable logic device (EPLD), an electrically erasable programmable logic device (EEPLD), a logic cell array (LCA), or a complex programmable logic devices (CPLD).

Example 15 is a non-transitory machine readable storage medium for facilitating enabling secure communication via attestation of multi-tenant configuration on accelerator devices. The non-transitory computer-readable storage medium of Example 15 having stored thereon executable computer program instructions that, when executed by one or more processors, cause the one or more processors to perform operations comprising: receive, by a programmable integrated circuit (IC) comprising the at least one processor, an incoming partial reconfiguration (PR) bitstream corresponding to a new PR persona to configure a region of the apparatus; perform, as part of a PR configuration sequence for the new PR persona, a first clear operation to clear previously-set persona configuration bits in the region; perform, as part of the PR configuration sequence subsequent to the first clear operation, a set operation to set new persona configuration bits in the region; and perform, as part of the PR configuration sequence, a second clear operation to clear memory blocks of the region that became unfrozen subsequent to the set operation, the second clear operation performed using a persona-dependent mask corresponding to the new PR persona.

In Example 16, the subject matter of Example 15 can optionally include wherein the security engine comprises a configuration manager and security enclave for the apparatus. In Example 17, the subject matter of Examples 15-16 can optionally include wherein the first clear operation is performed using a persona-independent mask that is publicly authenticated, and wherein the persona-independent mask is not under control of a tenant of the apparatus. In Example 18, the subject matter of Examples 15-17 can optionally include wherein the second clear operation is performed by loading the memory blocks with zeros.

In Example 19, the subject matter of Examples 15-18 can optionally include wherein the new PR persona comprises a PR bitstream used to configure the region. In Example 20, the subject matter of Examples 15-19 can optionally include wherein the programmable IC comprises at least one of a field programmable gate array (FPGA), a programmable array logic (PAL), a programmable logic array (PLA), a field programmable logic array (FPLA), an electrically programmable logic device (EPLD), an electrically erasable programmable logic device (EEPLD), a logic cell array (LCA), or a complex programmable logic devices (CPLD).

Example 21 is a system for facilitating enabling secure communication via attestation of multi-tenant configuration on accelerator devices. The system of Example 21 can optionally include a memory, and a security engine communicably coupled to the memory. The security engine of the system of Example 21 can be configured to receive an incoming partial reconfiguration (PR) bitstream corresponding to a new PR persona to configure a region of the apparatus; perform, as part of a PR configuration sequence for the new PR persona, a first clear operation to clear previously-set persona configuration bits in the region; perform, as part of the PR configuration sequence subsequent to the first clear operation, a set operation to set new persona configuration bits in the region; and perform, as part of the PR configuration sequence, a second clear operation to clear memory blocks of the region that became unfrozen subsequent to the set operation, the second clear operation performed using a persona-dependent mask corresponding to the new PR persona.

In Example 22, the subject matter of Example 21 can optionally include wherein the security engine comprises a configuration manager and security enclave for the apparatus. In Example 23, the subject matter of any one of Examples 21-22 can optionally include wherein the first clear operation is performed using a persona-independent mask that is publicly authenticated. In Example 24, the subject matter of any one of Examples 21-23 can optionally include wherein the persona-independent mask is not under control of a tenant of the apparatus.

In Example 25, the subject matter of any one of Examples 21-24 can optionally include wherein the second clear operation is performed by loading the memory blocks with zeros. In Example 26, the subject matter of any one of Examples 21-25 can optionally include wherein the new PR persona comprises a PR bitstream used to configure the region. In Example 27, the subject matter of any one of Examples 21-26 can optionally include wherein the apparatus comprises a hardware accelerator device comprising a programmable integrated circuit (IC). In Example 28, the subject matter of any one of Examples 21-27 can optionally include wherein the programmable IC comprises at least one of a field programmable gate array (FPGA), a programmable array logic (PAL), a programmable logic array (PLA), a field programmable logic array (FPLA), an electrically programmable logic device (EPLD), an electrically erasable programmable logic device (EEPLD), a logic cell array (LCA), or a complex programmable logic devices (CPLD).

Example 29 is an apparatus for facilitating enabling secure communication via attestation of multi-tenant configuration on accelerator devices according to implementations of the disclosure. The apparatus of Example 30 can comprise means for receiving, by a programmable integrated circuit (IC), an incoming partial reconfiguration (PR) bitstream corresponding to a new PR persona to configure a region of the apparatus; means for performing, as part of a PR configuration sequence for the new PR persona, a first clear operation to clear previously-set persona configuration bits in the region; means for performing, as part of the PR configuration sequence subsequent to the first clear operation, a set operation to set new persona configuration bits in the region; and means for performing, as part of the PR configuration sequence, a second clear operation to clear memory blocks of the region that became unfrozen subsequent to the set operation, the second clear operation performed using a persona-dependent mask corresponding to the new PR persona.

In Example 30, the subject matter of Example 29 can optionally include the apparatus further configured to perform the method of any one of the Examples 10 to 14.

Example 31 is at least one machine readable medium comprising a plurality of instructions that in response to being executed on a computing device, cause the computing device to carry out a method according to any one of Examples 9-14. Example 32 is an apparatus for facilitating enabling secure communication via attestation of multi-tenant configuration on accelerator devices, configured to perform the method of any one of Examples 9-14. Example 33 is an apparatus for facilitating enabling secure communication via attestation of multi-tenant configuration on accelerator devices comprising means for performing the method of any one of claims 9 to 14. Specifics in the Examples may be used anywhere in one or more embodiments.

The foregoing description and drawings are to be regarded in an illustrative rather than a restrictive sense. Persons skilled in the art can understand that various modifications and changes may be made to the embodiments described herein without departing from the broader spirit and scope of the features set forth in the appended claims. 

What is claimed is:
 1. An apparatus comprising: a security engine to: perform, as part of a PR configuration sequence for a new partial reconfiguration (PR) persona corresponding to a PR bitstream, a first clear operation to clear previously-set persona configuration bits in the region; perform, as part of the PR configuration sequence subsequent to the first clear operation, a set operation to set new persona configuration bits in the region; and perform, as part of the PR configuration sequence, a second clear operation to clear memory blocks of the region that became unfrozen subsequent to the set operation.
 2. The apparatus of claim 1, wherein the security engine comprises a configuration manager and security enclave for the apparatus.
 3. The apparatus of claim 1, wherein the first clear operation is performed using a persona-independent mask that is publicly authenticated, and wherein the second clear operation performed using a persona-dependent mask corresponding to the new PR persona.
 4. The apparatus of claim 3, wherein the persona-independent mask is not under control of a tenant of the apparatus.
 5. The apparatus of claim 1, wherein the second clear operation is performed by loading the memory blocks with zeros.
 6. The apparatus of claim 1, wherein the new PR persona comprises a PR bitstream used to configure the region.
 7. The apparatus of claim 1, wherein the apparatus comprises a hardware accelerator device comprising a programmable integrated circuit (IC).
 8. The apparatus of claim 7, wherein the programmable IC comprises at least one of a field programmable gate array (FPGA), a programmable array logic (PAL), a programmable logic array (PLA), a field programmable logic array (FPLA), an electrically programmable logic device (EPLD), an electrically erasable programmable logic device (EEPLD), a logic cell array (LCA), or a complex programmable logic devices (CPLD).
 9. A method comprising: performing, as part of a PR configuration sequence for a new partial reconfiguration (PR) persona corresponding to a PR bitstream, a first clear operation to clear previously-set persona configuration bits in the region; performing, as part of the PR configuration sequence subsequent to the first clear operation, a set operation to set new persona configuration bits in the region; and performing, as part of the PR configuration sequence, a second clear operation to clear memory blocks of the region that became unfrozen subsequent to the set operation.
 10. The method of claim 9, wherein the security engine comprises a configuration manager and security enclave for the apparatus.
 11. The method of claim 9, wherein the first clear operation is performed using a persona-independent mask that is publicly authenticated, and wherein the persona-independent mask is not under control of a tenant of the apparatus.
 12. The method of claim 9, wherein the second clear operation performed using a persona-dependent mask corresponding to the new PR persona, and wherein the second clear operation is performed by loading the memory blocks with zeros.
 13. The method of claim 9, wherein the new PR persona comprises a PR bitstream used to configure the region.
 14. The method of claim 9, wherein the programmable IC comprises at least one of a field programmable gate array (FPGA), a programmable array logic (PAL), a programmable logic array (PLA), a field programmable logic array (FPLA), an electrically programmable logic device (EPLD), an electrically erasable programmable logic device (EEPLD), a logic cell array (LCA), or a complex programmable logic devices (CPLD).
 15. A non-transitory machine readable storage medium comprising instructions that, when executed, cause at least one processor to at least: perform, as part of a PR configuration sequence for a new partial reconfiguration (PR) persona corresponding to a PR bitstream, a first clear operation to clear previously-set persona configuration bits in the region; perform, as part of the PR configuration sequence subsequent to the first clear operation, a set operation to set new persona configuration bits in the region; and perform, as part of the PR configuration sequence, a second clear operation to clear memory blocks of the region that became unfrozen subsequent to the set operation.
 16. The non-transitory machine readable storage medium of claim 15, wherein the security engine comprises a configuration manager and security enclave for the apparatus.
 17. The non-transitory machine readable storage medium of claim 15, wherein the first clear operation is performed using a persona-independent mask that is publicly authenticated, and wherein the persona-independent mask is not under control of a tenant of the apparatus.
 18. The non-transitory machine readable storage medium of claim 15, wherein the second clear operation performed using a persona-dependent mask corresponding to the new PR persona, and wherein the second clear operation is performed by loading the memory blocks with zeros.
 19. The non-transitory machine readable storage medium of claim 15, wherein the new PR persona comprises a PR bitstream used to configure the region.
 20. The non-transitory machine readable storage medium of claim 15, wherein the programmable IC comprises at least one of a field programmable gate array (FPGA), a programmable array logic (PAL), a programmable logic array (PLA), a field programmable logic array (FPLA), an electrically programmable logic device (EPLD), an electrically erasable programmable logic device (EEPLD), a logic cell array (LCA), or a complex programmable logic devices (CPLD). 